Zur Qualitativen Blutlehre

Ohne Zusammenfassung     

High sensitivity of free lambda and free kappa light chains for detection of intrathecal immunoglobulin synthesis in cerebrospinal fluid

Background – So far, an inflammation of the central nervous system (CNS) is diagnosed by immunoglobulin measurement in cerebrospinal fluid (CSF) and serum as well as by determination of the oligoclonal bands. With the free kappa and lambda light chains, new markers to diagnose intrathecal synthesis are available. Methods – In addition to routine diagnostic tests and the assessment of standard parameters, free immunoglobulin light chains were measured in the CSF of patients with neurological disorders. Results – A significant agreement was found between an increase in free kappa light chain CSF serum quotients and results of the currently widely applied method of oligoclonal band measurement for the detection of intrathecal immunoglobulin synthesis. A sensitivity of 95% and 100% specificity for free kappa light chain concentrations at a cut‐off of 0.41 mg/l was determined for free kappa light chains compared with oligoclonal bands. However, the free lambda light chains in 20 out of the 110 investigated samples were characterized by inconsistent behaviour. These otherwise unremarkable samples yielded increased CSF quotients, leading to the assumption that free lambda light chains represent a highly sensitive measure of intrathecal immunologlobulin synthesis. Thirteen of the 20 samples described above were obtained from patients with cerebral infarction, 4 samples derived from patients with cerebral paresis (primarily facial paresis), one sample was from a patient with multisystem atrophy and two were obtained from patients with migraine and neuralgia. Conclusion – These findings suggest that the high sensitivity of lambda light chains for the detection intrathecal immunoglobulin synthesis may be of benefit in establishing clinical diagnoses.     

Error calculation for the PSA quotient

ObjectiveProstate specific antigen (PSA) assays have significant measurement errors, but the error associated with the PSA quotient (free to total PSA) often remains unknown.MethodsWe used both Gaussian error calculation and measurement of imprecision to investigate the level of error associated with the PSA quotient.ResultsSurprisingly, we found that the error of the PSA quotient at low levels is markedly smaller than that of the total PSA value.ConclusionsThe PSA quotient should be calculated and considered as a clinically relevant value.     

Bemerkungen zu der Arbeit von Dr. Brieger

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Up-to-date knowledge about the association between multiple sclerosis and the reactivation of human endogenous retrovirus infections

Background

Although existing studies show that reactivation of the human endogenous retrovirus (HERVs) plays a leading role in multiple sclerosis (MS) progression, the practitioners are yet to establish effective approaches for managing MS without jeopardizing the patients’ immune systems.

Aim

To provide up-to-date knowledge on the specific roles played by the reactivation of the HERVs in the pathogenesis of MS.

Materials and methods

A systematic review of 70 peer-reviewed journals accessed via PubMed was conducted. The searches generated more than 600 sources that were evaluated based on three step in and exclusion criteria. The selected sources were critically analyzed vis-à-vis the paper’s hypothesis which posits that the HERVs reactivation does not directly cause the MS, but triggers a demyelination process by promoting the pathogenic effects of the retroviruses. The paper further documents the advancements in the therapeutic applications resulting from the immunohistological analysis and pathological studies aimed at minimizing the adverse consequences of the HERVs reactivation.

Results and discussions

Only three out of the 70 reviewed sources did not find provide evidence linking the reactivation of HERV and MS progression. On the other hand, overwhelming pieces of evidence confirm that the reactivations often drive the demyelinating plaques by initiating microglial inflammation. Pathological examinations reveal that the inflammatory monocytes (Ly6ChiCCR2 + CX3CR1lo) trigger the reactivation of the malignant T cells that are responsible for the progression of MS. These findings are promoting new discoveries as far as managing MS is concerned.

     

Rapid and reliable genotyping procedure for detection of alleles with mutations, deletion, or/and duplication of the CYP2D6 gene

Background

Polymorphisms of cytochrome P450 2D6 (CYP2D6) have a significant effect on the pharmacokinetics of most tricyclic antidepressants. More than 150 alleles lead to four distinct phenotypes of drug metabolism. The phenotypes are described as ultrarapid, extensive, intermediate, and poor metabolizers. Therapeutic plasma levels of CYP2D6 substrates may be difficult to achieve. Here we describe a rapid and reliable procedure for CYP2D6*4, *3, *6, and *9 genotyping.

Design and methods

Serum concentrations of venlafaxine and its pharmacologically active metabolite, O-desmethylvenlafaxine, were measured in patients treated with the antidepressant venlafaxine, a substrate of CYP2D6. The ODV/V ratio was used as an indicator of the CYP2D6 phenotype, with a higher ratio reflecting more rapid metabolism. Real-time PCR with fluorometric melting point analysis of the PCR products (LightCycler^®) is used to identify SNPs. Using quantitative PCR, gene deletion and gene duplication or multiplication are investigated by measurement of the fluorescence intensity quotient (q, N) of the CYP2D6 gene relative to that of the albumin gene as an internal standard.

Results

Melting curves are verified using DNA samples of known genotypes and by sequencing the PCR products. The genotypes and phenotypes that were detected correspond to each other.

Conclusion

A PCR procedure for the detection of CYP2D6 SNPs, deletions, and duplications is described and is rapid and reliable.